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UNITED STATES PATENT @EFIGE.

. WILL- AM M. DEAL, or PHILADELPHIA, PA -ASslGl iOR TO HIMSELF, JAMEs w. COURTNEY, AND ROBERT F. FRANKENFIELD, or SAME PLACE.

BALANCED SLIDE-VALVE.

SPECIFICATION forming part of Letters Patent No. 283,216, dated August 14, 1883.-

Application filed November 6, 1862. (X model.)

other engine that the friction between the i0 valve and its seat will be reduced, wear of the.

valve and seat correspondingly diminished, and less power required to move the valve than when the latter is subjected to the full pressure. A

My invention consists in combining a guide bar, connected to a balancing-piston, with a valve having guide-rollers at each end, and also in adapting said guide-bar to hearings in the chest, so as to insure parallel movement of all portions of the bar.

In the accompanying drawings, Figure 1 is a longitudinal section of part of a steam-engine cylinder, valve-chest, and valve with my improvements; Fig. 2, a perspective view of the valve and balancing device detached from the chest; Fig. 3, a transverse sectionof Fig. l.

A represents part of the cylinder of asteamengine, having the usual steam-inlet ports, w x, and exhaust-porty, and a chest, B, in which is .30 a slide-valve, D, of the ordinary form, operated by a valve-rod, E, in. the usual manner.

On the back of the valve D are wingsa a,

. which carry the journals of a pair of rollers,

12 b, adapted to a slotted bar, F, the latterbe- 3 5 ing suspended from a piston, G, which is properly packed, and is fitted to acylindrical opening', (1, in the top of the chest.

It will be seen that the pressure of steam exerted on the piston G tends to raisethe bar 7 0 F. and the valve, and thus counteracts, to a certain degree, the. downward pressure exerted upon the valve, so that by properly proportioning the area of the piston to the area of proper vertical guidance of the bar.

the valve exposed to downward pressure, said downward pressure may be balanced or nearly 4 5 balanced, and the friction between. the valve and its seat thus diminished, so as to reduce the wear of the surfaces in contact andlessen the power required .to'move the valve. Lugs f f are preferablyformed on the inside of the chest, to support the bar F and'relieve the valve from the weight of said bar and its piston when steam is cut off from the chest.

,The rollers 12 b are arranged one near each end of the valve, so that said valve is guided near each end, and the face of the same must movein a plane exactly parallel with the guide-bar, and in order to prevent change in the position of the guide-bar tending to inter fere withthe proper performance of its guiding duty, each end of the said bar bears against the end of the chest B, as shown in Fig. l, the bearingsurfaces of the bar and chest being rendered perfectly true, so as to insure the 2. The combination of the valve-chest B, the valve D and its rollers b, the guidebar F, having at each end a bearing against the end of the chest, and the piston G, connected to the bar F and exposed to the pressurein the chest, as set forth. A p

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM M. DEAL.

WVitnesses:

HARRY DRURY, HARRY SMITH. 

